Heterogeneous α‐Diimine Nickel Catalysts with Improved Catalytic Performance in Ethylene Polymerization

Abstract

Comprehensive SummaryHeterogenization can improve the thermal tolerance of olefin polymerization catalysts and result in good product morphology control, which are two important parameters for industrial polyethylene production. In this work, α‐diimine nickel catalysts bearing –OH or –ONa anchoring groups were designed and prepared. The anchoring groups can enable facile heterogenization of the catalysts on silica. The heterogeneous catalysts demonstrated enhanced thermal stabilities, along with high catalytic activity at 120 °C (up to 5.5 × 106 g·PE·mol·Ni–1·h–1). Furthermore, the heterogenization process results in the improvements of many other parameters, including polymer morphology control, catalytic activity (up to 1.9 × 107 g·PE·mol·Ni–1·h–1) and polyethylene molecular weight (Mn up to 2.3 × 106 g·mol–1). More importantly, the structure and properties of the polymer products can be controlled by catalyst structures, polymerization conditions and heterogenization to achieve good mechanical properties and elasticity.